Second Mesa, Arizona Weather Forecast Discussion

735
FXUS65 KFGZ 211749
AFDFGZ
Area Forecast Discussion
National Weather Service Flagstaff AZ
1049 AM MST Sun Sep 21 2025
.SYNOPSIS...Look for the development of isolated showers and
thunderstorms starting later today, with increasing coverage from
tonight through Monday. A low pressure system will remain
stationary off the southern California coast through Tuesday then
wobble over the southwest United States for the remainder of the
week. As a result, look for shower and thunderstorm chances at
times over northern Arizona through the week.
&&
.DISCUSSION...A low pressure system has developed off the central
California coast. The low will gradually take a southward path
becoming stationary off the southern California coast on Monday
and Tuesday. Starting Wednesday and toward the end of the week
the low will make a move north and east, wobbling over the
southwest United States. As a result, we are anticipating periods
of enhanced shower and thunderstorm activity through the coming
week.
For today and Monday...The low dips southward along the
California coast. Over Arizona the result will be the development
of a more southwesterly flow aloft which will tap into subtropical
moisture to the south of Arizona. In addition, northern Arizona
will be located under the right rear entrance region of a jet
stream max in the mid to upper levels which is a favorable
position for upward motion. The upward motion in combination with
increasing moisture will enhance instability/saturation across
portions of the area. As a result, look for the development of
shower and thunderstorm activity from around midday today through
Monday. The best chances appear to be on Monday when deeper
moisture arrives, generally south of a Grand Canyon to Window Rock
line. Pressure gradients will remain weak supporting light west
to southwest winds each day. Not much change in temperatures but
cloud cover will be on the increase with the push of moisture.
From Tuesday through the end of the week...This remains a
difficult forecast period. Once the low dips southward along the
California coast if gets somewhat cut-off from the main flow and
the "weatherman`s woe" saying still applies. We will continue to
go with unsettled conditions through this period with at least
slight chances for showers and storms each day as moisture lingers
across Arizona. The eventual path of the low will be critical to
how much moisture and precipitation Arizona sees. At this time it
appears the low will remain stationary off the southern California
coast through Tuesday then wobble to a position over the
southwest United States in response to an additional Pacific
system further north. A few solutions show the potential for heavy
rain toward the end of the week. You will want to check back as
there are sure to be updates to the current forecast scenario.
&&
.AVIATION...Sunday 21/18Z through Monday 22/18Z...Mainly VFR
conditions are forecast, but MVFR conditions possible in heavier
SHRA/TSRA. Isolated to scattered -SHRA/-TSRA developing
this afternoon, mainly south of the Interstate-40 corridor
through 00Z, increasing in coverage and spreading north and east
thereafter. Local MVFR ceilings possible after 08Z. Winds
becoming southwest at 10-15 kts gusting to 20 kts this afternoon
then diminishing to light and variable after 02Z - except locally
gusty near SHRA/TSRA.
OUTLOOK...Monday 22/18Z through Wednesday 24/18Z...Mainly VFR
conditions, but MVFR conditions possible in heavier SHRA/TSRA.
Scattered -SHRA/-TSRA Monday morning, shifting to mainly eastern
Arizona by afternoon. -SHRA/-TSRA activity becoming more isolated
Tuesday into Wednesday. Winds generally light less than 15 kts.
&&
.FIRE WEATHER...Today and Monday...Expect shower and thunderstorm
activity to slowly increase today, becoming more widespread tonight
and Monday. Daytime winds look to be from the southwest to west at 5
to 15 mph.
Tuesday through Thursday...A chance of showers and thunderstorms
will persist through the period as a low pressure system wobbles off
the southern California coast. Winds will be light, generally less
than 10 to 15 mph.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PUBLIC...McCollum
AVIATION...JJ
FIRE WEATHER...McCollum
For Northern Arizona weather information visit
weather.gov/flagstaff

NWS FGZ Office Area Forecast Discussion